Distinct codon usage signatures reflecting evolutionary and pathogenic adaptation in the Acinetobacter baumannii...

Area of Science:

• Microbiology and Evolutionary Genomics
• Bacterial Genetics and Phylogeny

Background:

• The genus Acinetobacter exhibits significant genomic and pathogenic diversity.
• Understanding codon usage patterns is crucial for deciphering evolutionary pressures and functional adaptations in bacteria.

Purpose of the Study:

• To investigate codon usage and amino acid bias in the genus Acinetobacter.
• To identify evolutionary forces (mutation vs. selection) influencing these patterns.
• To explore the implications for pathogenicity and biotechnology.

Main Methods:

• Analysis of genomic data using standard codon bias indices (GC content, RSCU, ENC, CAI).
• Application of neutrality and parity plots to assess mutational and selective pressures.
• Phylogenetic analysis using gyrB gene sequences to understand evolutionary relationships.

Main Results:

• Observed a dynamic GC content range across Acinetobacter species, with A. baumannii complex showing balanced GC distribution.
• Identified AT-rich preferred codons and correlations with GC composition, indicating mutational bias and selective pressure.
• Codon pair usage revealed functional congruence within the A. baumannii complex, supported by gyrB gene phylogeny.

Conclusions:

• Codon usage in Acinetobacter is shaped by a combination of mutational and selective forces, contributing to genomic and functional diversity.
• Disparities in codon usage between pathogenic and non-pathogenic species suggest potential genomic signatures of virulence.
• Further research is warranted to explore the pathogenic potential linked to these genomic signatures.